The present invention relates to backpacks and more particularly to a wheelable backpack.
The prior art illustrates that it is known to provide wheels for luggage, such as suitcases and trunks, but there has not been found, in the prior art, a wheeled, retractable backpack.
U.S. Pat. No. 4,314,624 discloses a wheeled piece of luggage that has on its back two spaced grooves with tubes being disposed in the groove with a handle at one end of the tubes and a wheel at the other end of each of the tubes, with the wheels being stored in cutouts in the back wall of the suitcase or trunk. The wheels can be turned into a wheelable condition from the cutouts by rotation of the tubes by the use of a helical screw thread and a nut on the end of the tubes which cause the tubes to rotate 90.degree. and thereby rotate the wheels out of the wheel cutouts.
U.S. Pat. No. 4,254,850 illustrates another arrangement for trunks and luggage having retractable wheels connected to a handle. The motion of each wheel is controlled by a cam slot so that the wheel moves out when the handle is extended, but returns to a storage position when the handle is retracted.
U.S. Pat. No. 4,588,055 discloses another arrangement for towing luggage, such as a suitcase or a trunk. In this patent the wall of the luggage includes a pair of fixed tubes, a pair of push pull tubes and a U-shaped tube wherein each end of the U-shaped tubes is connected to the push pull tubes. A pair of levers, one end of each being overlapped and hinged on the middle of the U-shaped tube and a pair of reverse L-shaped lengths which are fulcrumed at their angled part and are hinged on the other ends of the levers. By pushing down and pulling up the handle, the wheel units can be extended outward or retracted inward.
Each of these prior art arrangements, are relatively complex particularly the last patent, U.S. Pat. No. 4,588,055. There is no teaching in any of these patents, or other prior art patents uncovered in a search, that the techniques for the wheeling of trunks and suitcases can be adapted for use with a knapsack or backpack which is carried either by a pair of shoulder straps on the back of the person using the backpack or capable of being wheeled if the person so desires.